1. Technical Field
Devices and apparatuses consistent with the present invention relate to filament lamps, and, in particular, to filament lamps used for heating an object to be treated.
2. Related Art
In the process for manufacturing a solar cell, there are a thermal diffusion process for diffusing P-type semiconductors and a firing process for firing silver paste that is used as an electrode material. In the both processes, a semiconductor wafer or a glass substrate is heated to a high temperature, for example, 800 to 900° C. by using a thermal diffusion furnace and a firing furnace.
Meanwhile, this heat treatment device should uniformly heat the object to be treated to prevent difference in temperature according to location. For this reason, there has been proposed a filament lamp that is used as a light source, has a plurality of power supply paths in an arc tube, and can independently supply desired electric power to respective paths (see e.g., JP-A-2006-279008).
Further, since such a filament lamp has a plurality of power supply paths in the arc tube, terminals whose number corresponds to the number of the power supply paths should be provided to sealing sections of the lamp.
However, since the heating temperature of the object is higher in the above-mentioned process for manufacturing a solar cell, the electric power to be supplied to the lamp has also been increased. Meanwhile, there is a high demand for miniaturization rather in its size as opposed to an increase. That is, there is a demand for a filament lamp that has a plurality of independent power supply structures and meets the high input without the increase in size.